The code is giving the error:

An unhandled exception of type 'System.NullReferenceException' occurred in WindowsApplication2.exe

Additional information: Object reference not set to an instance of an object.


Here is the code:

OleDbConnection connToStore = new OleDbConnection( @"Provider=Microsoft.Jet.OLEDB.4.0; User Id=; Password=; Data source= "+db_storage);
connToStore.Open();

string cmdstr = "INSERT INTO trans_table( dataElement1, dataElement2, transformationDetail )" + "VALUES ('"+listBox_for_db1.Items[indexOfItemUnderMouseToDrag].ToString()+"','"+listBox_for_db2.Items[indexOfItemUnderMouseToDrag].ToString()+"','"+textBox_for_transformation.Text+ "')";

this.adapt.InsertCommand.Connection = connToStore;
this.adapt.InsertCommand.CommandText = cmdstr;
this.adapt.InsertCommand.ExecuteNonQuery();

connToStore.Close();
MessageBox.Show("successful");

Please show your source in its entirety and including the line number of the error.
It looks as though you haven't defined an OleDbCommand, but I can't see what you're doing with the adapter ("this.adapt.").

Anyhow; take a look at the following tutorial:
ADO.NET: Retrieve Data using OLE DB: http://dotnetjunkies.com/QuickStartv...odtreader.aspx
Simple ADO.NET Database Read, Insert, Update and Delete using C#: http://www.codeproject.com/dotnet/si...0&select=37317

- Adam Kahtava [http://adam.kahtava.com]

it also seem that u have not created the reference of adapt i.e. adapt variable do not have reference.

Bijgupt